Diones and their use as polymer stabilizers

ABSTRACT

Compounds of the formula I ##STR1## wherein A is alkylidene or optionally alkylated vinylene, B is a group of the formula II ##STR2## wherein R 1  and R 2  are alkyl, R 3 , R 4  and R 5  are hydrogen or alkyl and n is 0, 1 or 2 and m is 1 or 2, and X is identical to B if m equals 1 or X is methylene if m equals 2, as stabilizers for organic material.

This is a divisional of application Ser. No. 672,566, filed on Mar. 31,1976 now U.S. Pat. No. 4,069,197 which issued on Jan. 17, 1978.

The present invention relates to N-heterocyclic compounds, theirmanufacture, their use for stabilising organic material and the organicmaterial stabilised with the aid of these compounds.

It is known to employ derivatives of sterically hindered phenols asstabilisers, for organic polymers, against thermo-oxidative degradationof the polymers or against light ageing of the polymers. Many of thesephenol derivatives have the disadvantage of objectionably discolouringthe organic polymer, either already during their incorporation or by theaction of light or on contact with industrial waste gases or also oncontact with hot water, which greatly limits their industrialapplicability. n-Octadecylβ-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propionate, for example, which isstructurally related to the new compounds, is known and commerciallyavailable; compare British patent specification No. 990,304. Newcompounds have now been found which, surprisingly, are not onlyoutstandingly suitable for stabilising organic materials, in particularorganic polymers, but also, at the same time, remain colourless underthe conditions mentioned and protect the organic material againstdiscolouration for a long time. This means that the new compoundsstabilise the organic material both against degradation and againstdiscolouration.

The invention thus relates to compounds of the formula I ##STR3##wherein A is alkylidene or optionally alkylated vinylene, B is a groupof the formula II ##STR4## wherein R₁ and R₂ are alkyl, R₃, R₄ and R₅are hydrogen or alkyl and n is 0, 1 or 2 and m is 1 or 2, and X isidentical to B if m equals 1 or X is methylene if m equals 2.

A as alkylidene is, for example, methylene which is optionallysubstituted by one or two alkyl groups, in particular with 1-24 C atoms,above all methylene substituted by one or, in particular two, alkylgroups with 1-6 C atoms, such as, above all, isopropylidene orethylidene. A as optionally alkylated vinylene is vinylene which issubstituted, in particular, by alkyl with 1-12 C atoms, the alkylsubstituent being, in particular adjacent to a ring N atom, for examplevinylene which is substituted by alkyl with 1-6 C atoms, such as, inparticular, methylvinylene.

R₁ and R₂ as alkyl are, for example, independently of one another,straight-chain or branched alkyl with 1-12 C atoms, in particular 1-8 Catoms, such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec.-butyl,tert.-butyl, 2-ethylbutyl and n-octyl. α-Branched alkyl radicals with3-8 C atoms, in particular tert.-butyl, are preferred.

R₃, R₄ and R₅ as alkyl are, for example, independently of one another,straight-chain or branched alkyl with 1-12 C atoms, in particular 1-8,and above all 1-4. In particular, methyl is suitable. However, R₃, R₄and R₅ are, above all, hydrogen.

Compounds of the formula I, wherein A is alkylidene with 1-13 C atoms orvinylene which is optionally substituted with alkyl with 1-6 C atoms,adjacent to the ring N atom, R₁ and R₂ are alkyl with 1-8 C atoms, R₃,R₄ and R₅ are hydrogen, n is 0, 1 or 2, m is 1 or 2 and X is identicalto B if m equals 1 or X is methylene if m equals 2, are preferred.

Compounds of the formula I, wherein A is isopropylidene, ethylidene ormethylvinylene, in which the methyl substituent is adjacent to the ringN atom, R₁ and R₂ are α-branched alkyl with 3-8 C atoms, R₃, R₄ and R₅are hydrogen, n is 0, 1 or 2, m is 1 or 2 and X is identical to B if mequals 1 or X is methylene if m equals 2, are particularly preferred.

In the preferred compounds of the formula I, R₁ and R₂ are, inparticular, tert.-butyl.

In the preferred compounds of the formula I, n is, in particular, 2.

Examples which may be mentioned are:

1.1,1'-Methylene-bis-[3-[3-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propionyl-oxyethyl]-5,5-dimethyl-hydantoin].

2.1,3-Di-[3-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propionyl-oxyethyl]-5,5-dimethylhydantoin.

3.1,3-Di-[3-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propionyl-oxyethyl]-6-methyl-1,2,3,4-tetrahydro-pyrimidine-2,4-dione.

The compounds of the formula I can be manufactured by methods which arein themselves known.

For example, the procedure followed can be to react an acid of theformula II ##STR5## wherein R₁, R₂, R₃, R₄ and n have the above meaning,or a reactive derivative thereof, with an alcohol of the formula III##STR6## wherein A has the above meaning, B' is a radical --CH₂--CH(R₅)OH, m is 1 or 2 and X' is identical to B' if m equals 1 or X' ismethylene if m equals 2.

A reactive derivative of an acid of the formula II is, for example, anester, in particular an alkyl ester with preferably 1-6 C atoms, such asthe methyl ester, an anhydride, for example a mixed anhydride or, inparticular, an anhydride of two mols of an acid of the formula II, and ahalide, for example a chloride.

In the case of an ester the reaction is suitably carried out in thepresence of catalytic amounts of a base, such as inorganic base, forexample oxides, alkoxides, hydroxides and amides of alkali metals andalkaline earth metals, such as sodium methylate, sodium hydroxide,potassium hydroxide and sodium amide. Preferably, about 2 mols of esterper mol of alcohol are used.

In the case of a halide the reaction is preferably carried out in thepresence of an acid-binding agent, such as an organic or inorganic base,for example a tertiary amine, such as trimethylamine and triethylamine,or an alkali metal hydroxide, such as sodium hydroxide or potassiumhydroxide. About 2 mols of acid-binding agent and about 2 mols of halideare suitably used per mol of alcohol. Solvents are advantageously usedfor the reaction, for example amides, such as dimethylformamide anddimethylacetamide, aromatic hydrocarbons, such as benzene and toluene,or ethers, such as diethyl ether and tetrahydrofurane.

If the free acid of the formula II is used, the reaction isadvantageously carried out in the presence of an acid catalyst, such asa strong acid, for example hydrochloric acid, sulphuric acid or asulphonic acid, such as p-toluenesulphonic acid. The water formed duringthe esterification is removed in a suitable manner, for example byazeotropic distillation or by adding a water-binding agent, for examplephosphorus pentoxide or a carbodiimide. In particular, about 2 mols ofacid of the formula II are used per mol of alcohol.

The starting materials are known or, if they are new, can bemanufactured analogously to the manufacture of known compounds bymethods which are in themselves known. Thus acids or esters of theformula II are known, for example from British patent specification No.990,304, or, if they are new, can be manufactured analogously to thepreviously known methods. Other reactive derivatives of the acids of theformula II can be manufactured from the acids in a known manner, forexample anhydrides by means of dehydrating agents, such as phosphoruspentoxide, and halides by means of halogenating agents, such asphosphorus oxyhalides, for example phosphorus oxychloride, or sulphurylhalides, such as sulphuryl chloride. The alcohols of the formula III areknown and can be obtained, for example, in the customary manner from thecorresponding NH compounds with, for example, R₅ -substituted ethyleneoxide.

According to the present invention, the compounds of the formula I canbe used as stabilisers for organic substrates. Examples of possiblesubstrates are:

1. Polymers which are derived from hydrocarbons with single or doubleunsaturation, such as polyolefins, for example polyethylene, which canoptionally be crosslinked, polypropylene, polyisobutylene,polymethylbutene-1, polymethylpentene-1, polyisoprene, polybutadiene,polystyrene, polyisobutylene, copolymers of the monomers on which thehomopolymers mentioned are based, such as ethylenepropylene copolymers,propylene-butene-1 copolymers, propyleneisobutylene copolymers,styrene-butadiene copolymers and terpolymers of ethylene and propylenewith a diene, such as, for example, hexadiene, dicyclopentadiene orethylidenenorbornene; mixtures of the abovementioned homopolymers, suchas, for example, mixtures of polypropylene and polyethylene,polypropylene and polybutene-1, or polypropylene and polyisobutylene.

2. Vinyl polymers containing halogen, such as polyvinyl chloride,polyvinylidene chloride, and polyvinyl fluoride, but alsopolychloroprene and chlorinated rubbers.

3. Polymers which are derived from α,β-unsaturated acids and theirderivatives, such as polyacrylates and polymethacrylates,polyacrylamides and polyacrylonitrile, as well as their copolymers withother vinyl compounds, such as acrylonitrile/butadiene/styrene,acrylonitrile/styrene and acrylonitrile/styrene/acrylic estercopolymers.

4. Polymers which are derived from unsaturated alcohols and amines ortheir acyl derivatives or acetals, such as polyvinyl alcohol, polyvinylacetate, polyvinyl stearate, polyvinyl benzoate, polyvinyl maleate,polyvinyl butyral, polyallyl phthalate, polyallyl melamine and theircopolymers with other vinyl compounds, such as ethylene/vinyl acetatecopolymers.

5. Homopolymers and copolymers which are derived from epoxides, such aspolyethylene oxide or the polymers which are derived from bis-glycidylethers.

6. Polyacetals, such as polyoxymethylene and polyoxyethylene, as well asthose polyoxymethylenes which contain ethylene oxide as a comonomer.

7. Polyphenylene oxides.

8. Polyurethanes and polyureas.

9. Polycarbonates.

10. Polysulphones.

11. Polyamides and copolyamides which are derived from diamines anddicarboxylic acids and/or from aminocarboxylic acids or thecorresponding lactams, such as polyamide 6, polyamide 6/6, polyamide6/10, polyamide 11 and polyamide 12.

12. Polyesters which are derived from dicarboxylic acids and dialcoholsand/or from hydroxycarboxylic acids or the corresponding lactones, suchas polyethylene glycol terephthalate or poly-1,4-dimethylol-cyclohexaneterephthalate.

13. Crosslinked polymers which are derived from aldehydes on the onehand and phenols, ureas and melamines on the other, such asphenol-formaldehyde, urea-formaldehyde and melamine-formaldehyde resins.

14. Alkyd resins, such as glycerol-phthalic acid resins and theirmixtures with melamine-formaldehyde resins.

15. Unsaturated polyester resins which are derived from copolyesters ofsaturated and unsaturated dicarboxylic acids with polyhydric alcohols,with vinyl compounds as crosslinking agents, and also theirhalogen-containing modifications of low inflammability.

16. Natural polymers, such as cellulose, rubber, proteins and theirpolymer-homologously chemically modified derivatives, such as celluloseacetates, cellulose propionates and cellulose butyrates, or thecellulose ethers, such as methylcellulose.

17. High molecular monomeric substances, for example mineral oils,animal and vegetable fats, oils and waxes, or oils, waxes and fats basedon synthetic esters.

The use of the compounds of the formula I for stabilising homopolymersand copolymers of olefines, such as the substrates mentioned under 1,and of polyamides and polyurethanes is of particular importance.

The compounds of the formula I are generally incorporated into thesubstrates in a concentration of 0.01 to 5% by weight, calculatedrelative to the material to be stabilised. Preferably, 0.05 to 2.0, andparticularly preferentially 0.1 to 1.0% by weight of the compounds,calculated relative to the material to be stabilised, are incorporatedinto the latter. The incorporation can take place, for example, bymixing in at least one of the compounds of the formula I and optionallyfurther additives according to the methods customary in the art, beforeor during shaping, or by applying the dissolved or dispersed compoundsto the polymer, if appropriate with subsequent evaporation of thesolvent.

In the case of crosslinked polyethylene, the compounds of the formula Iare appropriately added before crosslinking. The compounds of theformula I can also be added before or during the polymerisation.

As further additives, together with which the stabilisers according tothe invention can be employed, there should be mentioned:

1. Antioxidants of the aminoaryl and hydroxyaryl series.

In the case of the latter, the sterically hindered phenol compounds ofthe following classes should be mentioned:

1.1. Simple 2,6-dialkylphenols, such as, for example,2,6-di-tert.butyl-4-methylphenol, 2-tert.butyl-4,6-dimethylphenol,2,6-di-tert.butyl-4-methoxymethylphenol and2,6-dioctadecyl-4-methylphenol.

1.2. Derivatives of alkylated hydroquinones, such as, for example,2,5-di-tert.butyl-hydroquinone, 2,5-di-tert.amylhydroquinone,2,6-di-tert.butyl-hydroquinone, 2,5-di-tert.butyl-4-hydroxy-anisole,3,5-di-tert.butyl-4-hydroxy-anisole andtris-(3,5-di-tert.butyl-4-hydroxyphenyl) phosphite.

1.3. Hydroxylated thiodiphenyl ethers, such as, for example,2,2'-thio-bis-(6-tert.butyl-4-methylphenol),2,2'-thio-bis-(4-octylphenol),4,4'-thio-bis-(6-tert.butyl-3-methylphenol),4,4'-thio-bis-(3,6-di-sec.amylphenol) and4,4'-thio-bis-(6-tert.butyl-2-methylphenol).

1.4. Alkylidene-bisphenols, such as, for example,2,2'-methylene-bis-(6-tert.butyl-4-methylphenol),2,2'-methylene-bis-(6-tert.butyl-4-ethylphenol),4,4'-methylene-bis-(6-tert.butyl-2-methylphenol),4,4'-methylene-bis-(2,6-di-tert.butylphenol),2,6-di-(3-tert.butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,2,2'-methylene-bis -[4-methyl-6-(α-methylcyclohexyl)-phenol],1,1-bis-(3,5-dimethyl-2-hydroxyphenyl)-butane,1,1-bis-(5-tert.butyl-4-hydroxy-2-methylphenyl)-butane,2,2-bis-(5-tert.butyl-4-hydroxy-2-methylphenyl)-butane,2,2-bis-(3,5-di-tert.butyl-4-hydroxyphenyl)-propane,1,1,3-tris-(5-tert.butyl-4-hydroxy-2-methylphenyl)-butane,2,2-bis-(5-tert.butyl-4-hydroxy-2-methylpheny)-4-n-dodecylmercapto-butane,1,1,5,5-tetra-(5-tert.butyl-4-hydroxy-2-methylphenyl)-pentane andethylene glycol bis-[3,5-bis-(3'-tert.butyl-4'-hydroxyphenyl)-butyrate].

1.5. O-, and S-benzyl compounds, such as, for example,3,5,3',5'-tetra-tert.butyl-4,4'-dihydroxydibenzyl ether,4-hydroxy-3,5-dimethylbenzyl-mercaptoacetic acid octadecyl ester,tri-(3,5-di-tert.butyl-4-hydroxybenzyl)-amine andbis-(4-tert.butyl-3-hydroxy-2,6-dimethylbenzyl)-dithiol terephthalate.

1.6. Hydroxybenzylated malonic esters, such as, for example,2,2-bis-(3,5-di-tert.butyl-4-hydroxybenzyl)-malonic acid dioctadecylester, 2-(3-tert.butyl-4-hydroxy-5-methylbenzyl)-malonic aciddioctadecyl ester, 2,2-bis-(3,5-di-tert.butyl-4-hydroxybenzyl)-malonicacid didodecylmercaptoethyl ester and2,2-bis-(3,5-di-tert.butyl-4-hydroxybenzyl) malonic aciddi-(4-tert.octylphenyl) ester.

1.7. Hydroxybenzyl-aromatics, such as, for example,1,3,5-tri-(3,5-di-tert.butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,1,4-di-(3,5-di-tert.butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzeneand 2,4,6-tri-(3,5-di-tert.butyl-4-hydroxybenzyl)-phenol.

1.8. s-Triazine compounds, such as, for example,2,4-bis-octylmercapto-6-(3,5-di-tert.butyl-4-hydroxy-anilino)-s-triazine,2-octylmercapto-4,6-bis-(3,5-di-tert.butyl-4-hydroxy-anilino)-s-triazine,2-octylmercapto-4,6-bis-(3,5-di-tert.butyl-4-hydroxy-phenoxy)-s-triazine,2,4,6-tris-(3,5-di-tert.butyl-4-hydroxyphenoxy)-s-triazine,2,4,6-tris-(3,5-di-tert.butyl-4-hydroxyphenylethyl)-s-triazine and1,3,5-tris-(3,5-di-tert.butyl-4-hydroxybenzyl)-isocyanurate.

1.9. Amides of 3,5-di-tert.butyl-4-hydroxyphenyl-propionic acid, suchas, for example,1,3,3-tri-(3,5-di-tert.butyl-4-hydroxyphenyl-propionyl)-hexahydro-s-triazineandN,N'-di-(3,5-di-tert.butyl-4-hydroxyphenyl-propionyl)-hexamethylenediamine.

1.10 Esters of 3,5-di-tert.butyl-4-hydroxyphenyl-propionic acid withmonohydric or polyhydric alcohols, such as, for example, with methanol,ethanol, octadecanol, 1,6-hexanediol, 1,4-nonanediol, ethylene glycol,1,2-propanediol, diethylene glycol, thiodiethylene glycol, neopentylglycol, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolethane, trimethylolpropane, pentaerythritol,tris-hydroxyethylisocyanurate and4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane.

1.11. Esters of 5-tert.butyl-4-hydroxy-3-methylphenylpropionic acid withmonohydric or polyhydric alcohols, such as, for example, with methanol,ethanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, diethylene glycol, thiodiethylene glycol, neopentylglycol, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolethane, trimethylolpropane, pentaerythritol,tris-hydroxyethyl-isocyanurate and4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane.

1.12. Esters of 3,5-di-tert.butyl-4-hydroxyphenylacetic acid withmonohydric or polyhydric alcohols, such as, for example, with methanol,ethanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, diethylene glycol, thiodiethylene glycol, neopentylglycol, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylolethane, trimethylolpropane, pentaerythritol,tris-hydroxyethylisocyanurate and4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2,2,2]octane.

1.13. Acylaminophenols, such as, for example,N-(3,5-di-tert.butyl-4-hydroxyphenyl)-stearic acid amide andN,N'-di-(3,5-di-tert.butyl-4-hydroxyphenyl)-thio-bis-acetamide.

1.14. Benzylphosphonates, such as, for example,3,5-di-tert.butyl-4-hydroxybenzyl-phosphonic acid dimethyl ester,3,5-di-tert.butyl-4-hydroxybenzyl-phosphonic acid diethyl ester,3,5-di-tert.butyl-4-hydroxybenzyl-phosphonic acid dioctadecyl ester and5-tert.butyl-4-hydroxy-3-methylbenzyl-phosphonic acid dioctadecyl ester.

2. UV absorbers and light stabilisers, such as:

2.1. 2-(2'-Hydroxyphenyl)-benztriazoles, for example the 5'-methyl-,3',5'-di-tert.butyl-, 5'-tert.butyl-, 5-chloro-3',5'-di-tert.butyl-,5'-chloro-3'-tert.butyl-5'-methyl-, 3'-sec. butyl-5'-tert.butyl-,3'-[α-methylbenzyl]-5'-methyl-, 3'-[α-methylbenzyl]-5'-methyl-5-chloro-,4'-octoxy-, 3',5'-di-tert.amyl-, 3'-methyl-5'-carbomethoxyethyl- and5-chloro-3',5'-di-tert.amyl-derivative.

2.2. 2,4-Bis-(2'-hydroxyphenyl)-6-alkyl-s-triazines, for example the6-ethyl- or 6-undecyl- derivative.

2.3. 2-Hydroxy-benzophenones, for example the 4-hydroxy-, 4-methoxy-,4-octoxy-, 4-decyloxy-, 4-dodecyloxy-, 4,2',4'-trihydroxy- or2'-hydroxy-4,4'-dimethoxy- derivative.

2.4. 1,3-Bis-(2'-hydroxybenzoyl)-benzenes, for example1,3-bis-(2'-hydroxy-4'-hexyloxy-benzoyl)-benzene,1,3-bis-(2'-hydroxy-4'-octoxy-benzoyl)-benzene and1,3-bis-(2'-hydroxy-4'-dodecyloxy-benzoyl)-benzene.

2.5. Aryl esters of optionally substituted benzoic acids, such as, forexample, phenyl salicylate, octylphenyl salicylate, dibenzoylresorcinol,bis-(4-tert.butylbenzoyl)-resorcinol, benzoylresorcinol and3,5-di-tert.butyl-4-hydroxybenzoic acid 2,4-di-tert.butyl-phenyl esteror octadecyl ester or 2-methyl-4,6-di-tert.butyl-phenyl ester.

2.6. Acrylates, for example α-cyano-β,β-diphenylacrylic acid ethyl esteror isooctyl ester, α-carbomethoxy-cinnamic acid methyl ester,α-cyano-β-methyl-p-methoxy-cinnamic acid methyl ester or butyl ester andN-(β-carbomethoxy-vinyl)-2-methylindoline.

2.7. Nickel compounds, for example nickel complexes of2,2'-thio-bis-(4-tert.octylphenol), such as the 1:1 and 1:2 complex,optionally with other ligands, such as n-butylamine, nickel complexes ofbis-(4-tert.octylphenol)-sulphone, such as the 2:1 complex, optionallywith other ligands, such as 2-ethylcaproic acid, nickeldibutyldithiocarbamate, nickel salts of4-hydroxy-3,5-di-tert.butylbenzyl-phosphonic acid monoalkyl esters, suchas the methyl, ethyl or butyl ester, the nickel complex of2-hydroxy-4-methyl-phenyl-undecylketoxime.

2.8. Oxalic acid diamides, for example 4,4'-di-octyloxyoxanilide,2,2'-di-octyloxy-5,5'-di-tert.butyl-oxanilide and2,2'-di-dodecyloxy-5,5'-di-tert.butyl-oxanilide.

2.9. 2,2,6,6-Tetramethylpiperidines, such as2,2,6,6-tetramethyl-4-stearoyloxypiperidine andbis-(2,2,6,6-tetramethyl-4-hydroxypiperidine)-sebacate.

3. Phosphites, such as triphenyl phosphite, diphenylalkyl phosphites,phenyldialkyl phosphites, tri-(nonylphenyl) phosphite, trilaurylphosphite, trioctadecyl phosphite,3,9-di-isodecyloxy-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5,5]-undecaneand tri-(4-hydroxy-3,5-di-tert.butylphenyl) phosphite.

4. Compounds which destroy peroxide, such as esters of β-thiodipropionicacid, for example the lauryl, stearyl, myristyl or tridecyl ester, saltsof 2-mercaptobenzimidazole, for example the zinc salt, anddiphenylthiourea.

5. Specific polyamide stabilisers, such as copper salts in combinationwith iodides and/or further phosphorus compounds and salts of divalentmanganese.

6. Basic co-stabilisers, such as polyvinylpyrrolidone, melamine,benzoguanamine, triallyl cyanurate, dicyandiamide, urea derivatives,hydrazine, derivatives, amines, polyamides, polyurethanes, and alkalimetal salts and alkaline earth metal salts of higher saturated orunsaturated fatty acids, such as, for example, the laurates, myristates,palmitates, stearates, oleates or ricinoleates of calcium, magnesium,zinc, sodium or potassium. These salts are advantageously added, inconcentrations of 0.1-40% by weight, preferably 1-10% by weight, to thestabiliser according to the invention before being incorporated into thematerial to be stabilised.

7. Specific PVC stabilisers, such as organic tin compounds, organic leadcompounds and Ba/Cd salts of fatty acids.

8. Nucleating agents, such as 4-tert.butyl-benzoic acid, adipic acid anddiphenylacetic acid.

9. Other additives, such as plasticisers, lubricants, for exampleglycerol monostearate, emulsifiers, antistatic agents, flameproofingagents, pigments, carbon black, asbestos, glass fibres, kaolin and talc.

The invention is described in more detail in the examples which follow.Percentages (%) therein denote percentages by weight and parts denoteparts by weight. The temperatures are indicated in degrees Centigrade.

EXAMPLE 1

6.42 g (0.018 mol) of1,1'-methylene-bis-[3-(3-hydroxyethyl)-5,5-dimethyl]-hydantoin, 10 g(0.036 mol) of 3-(3,5-di-tert.butyl-4-hydroxyphenyl)-propionic acid and1 g of p-toluenesulphonic acid are first introduced into 100 ml oftoluene and the mixture is heated for 1 hour under reflux under a waterseparator, whilst stirring. The mixture is then neutralised with sodiumacetate and extracted with water and the organic phase is completelyconcentrated under reduced pressure. The residue is recrystallised frommethanol. The1,1'-methylene-bis-[3[3-(3,5-tert.butyl-4-hydroxyphenyl)-propionyl-oxyethyl]-5,5-dimethylhydantoin]thus obtained melts at 148° C., Stabiliser No. 1.

If the 1,1'-methylene-bis-[3-(2-hydroxyethyl)-5,5-dimethyl]-hydantoin inthis example is replaced by an equimolar amount of1,3-di-(2-hydroxyethyl)-5,5-dimethyl-hydantoin or1,3-di-(2-hydroxyethyl)-6-methyl-1,2,3,4-tetrahydropyrimidine-2,4-dioneand the procedure followed is otherwise identical,1,3-di-[3-(3,5-di-tert.butyl-4-hydroxyphenyl)-propionyl-oxyethyl]-5,5-dimethyl-hydantoin,Stabiliser No. 2, or1,3-di-[3-(3,5-di-tert.butyl-4-hydroxyphenyl)-propionyl-oxyethyl]-6-methyl-1,2,3,4-tetrahydro-pyrimidine-2,4-dione,Stabiliser No. 3, is obtained.

These compounds are obtained as viscous, light brown oils and can befurther purified by column chromatography.

EXAMPLE 2

100 parts of polypropylene (melt index 2.6 g/10 minutes, 230° C./2,160g) are intensively mixed for 10 minutes in a shaking apparatus with 0.2part of one of the additives listed in Table 1 which follows.

The resulting mixture is kneaded in a Brabender plastograph for 10minutes at 200° and the mass obtained in this way is subsequentlypressed in a sheet press at 260° platen temperature to give 1 mm thicksheets, from which strips 1 cm wide and 17 cm long are punched.

The activity of the additives incorporated into the test strips istested by heat ageing in a circulating air oven at 135° and 149°, withan additive-free test strip serving for comparison. Three test strips ofeach formulation are employed for the test. The end point is defined asthe incipient decomposition of the test strip, which can be easilyrecognised by complete embrittlement. The results are indicated in days.

                  Table 1                                                         ______________________________________                                                 Days to reach incipient decomposition at                             ______________________________________                                        Stabiliser No.                                                                           135°    149°                                         ______________________________________                                        without additive                                                                          1             <1                                                  2          157            45                                                  1          142            40                                                  3          133            32                                                  ______________________________________                                    

EXAMPLE 3

The test specimens described in Example 2 are furthermore tested fortheir colour stability, namely:

(a) after incorporation (Table 2, column 2),

(b) after 500 hours exposure in a Xenotest apparatus, by Messrs. Hanau(Table 2, column 3), and

(c) after treatment with boiling water for 1 week (Table 2, column 4).

An empirical colour scale in which 5 denotes colourlessness, 4 denotes aslight discoloration which is just perceptible and 3, 2, 1 and <1 denotea successively increasing discoloration is used for the assessment.

                  Table 2                                                         ______________________________________                                                  Colour assessement                                                            according to the scale 1-5                                          ______________________________________                                                    after       after     boiling water                               Stabiliser No.                                                                            incorporation                                                                             exposure  for 1 week                                  ______________________________________                                        without additive                                                                          5           5         4-5                                         2           4-5         5         4-5                                         1           5           5         4-5                                         3           4-5         5         4-5                                         ______________________________________                                    

EXAMPLE 4 Assessment of the resistance to "gas fading"

A piece of cotton fabric is soaked with a 1% strength solution of anadditive of the Table 3 below, and is then dried. The piece of fabrictreated in this way is exposed, in a closed chamber, to the off-gases ofa row of natural gas burners at a temperature of 100° for one hour. Thepiece of fabric is then extracted with a mixture of 100 ml ofdimethylacetamide and 1 ml of piperidine. The intensity of thecoloration (usually yellow) of the resulting solution is considered ameasure of the resistance to gas fading of the additive investigated.

An empirical colour scale in which 5 denotes colourlessness, that is tosay very good resistance to gas fading, 4 denotes a slight discolorationwhich is just perceptible and 3, 2 and 1 denote a successivelyincreasing discoloration was used for the Table 3.

                  Table 3                                                         ______________________________________                                                 Colour assessment according to the scale 1.5,                        Stabiliser No.                                                                         after gas fading                                                     ______________________________________                                        1        4-5                                                                  3        4-5                                                                  ______________________________________                                    

What we claim is:
 1. Compounds of the formula ##STR7## wherein A isvinylene or alkylated vinylene, B is a group of the formula ##STR8##wherein R₁ and R₂ are alkyl, R₃, R₄ and R₅ are hydrogen or alkyl and nis 0, 1 or 2 and m is 1 or 2, and X is identical to B if m equals 1 or Xis methylene if m equals
 2. 2. Compound according to claim 1, wherein Ais vinylene or vinylene substituted with alkyl with 1-6 C atoms,adjacent to the ring N atom, R₁ and R₂ are alkyl with 1-8 C atoms, R₃,R₄ and R₅ are hydrogen, n is 0, 1 or 2, m is 1 or 2 and X is identicalto B if m equals 1 or X is methylene if m equals
 2. 3. Compoundaccording to claim 1, wherein A is methylvinylene, in which the methylsubstituent is adjacent to the ring N atom, R₁ and R₂ are α-branchedalkyl with 3-8 C atoms, R₃, R₄ and R₅ are hydrogen, n is 0, 1 or 2, m is1 or 2 and X is identical to B if m equals 1 or X is methylene if mequals
 2. 4. Compound according to claim 1, wherein n is
 2. 5. Compoundaccording to claim 1, which is1,3-di-[3-(3,5-di-tert.-butyl-4-hydroxyphenyl)-propionyl-oxyethyl]-6-methyl-1,2,3,4-tetrahydro-pyrimidine-2,4-dione.6. A composition of matter comprising a synthetic organic polymer andfrom 0.01 to 5% by weight of a stabilizing compound of claim
 1. 7. Acomposition of claim 6 wherein the organic material is polyolefine. 8.Stabilised organic material according to claim 7, wherein thepolyolefine is polypropylene.